Chromium (III) oxide is known as a vapor-phase catalyst for the reaction of chlorocarbons, hydrochlorocarbons, hydrofluorocarbons, hydrochlorofluorocarbons, and chlorofluorocarbons with hydrogen fluoride to produce more fluorinated or more highly fluorinated products. The active species is believed to be the fluorinated form of Cr2O3 such as oxyfluoride which in turn takes part in a halogen exchange reaction with the hydrocarbons or chlorinated hydrocarbons to form fluorinated or more highly fluorinated products. In this reaction the chromium oxyfluoride exchanges it fluoride atom with the chlorine atoms of the reactant to form the fluorinated product and the catalyst then is in a chlorinated form. The chlorinated form of the catalyst is then fluorinated back to its oxyfluoride form by the interaction with HF which is always present in molar excess. It has been discovered that the catalytic activity of chromium (III) oxide as a fluorination catalyst can vary as a function of the process for the preparation of the chromium (III) oxide. It is also understood that the surface area and particle size of the chromium (III) oxide play significant role in its catalytic activity. Additionally, it is also now recognized that it would be desirable that chromium (III) oxide that is highly effective and selective as a fluorination catalyst be available by a process for its production such that it would be relatively inexpensively produced from inexpensive starting materials and be useful as a catalyst, particularly in industrially significant fluorination reactions.